Device for effectively dissipating heat from machine parts



Jan. 2l, 1936. A, L. R. BERNARD 2,028,434

DEVICE'AFOR EFFECTIVELY DISSIPATING HEAT FROM MACHINE PARTS Filed DGO. 17, 1934 Patented Jan. 2l, 19362' UNITED STATES DEVICE FOR EFFECTIVELY `DISSIPATING BEAT FROM MACHINE PARTS LAuguste Louie nene Bernard, aeeeeeed, me er Rueil-Malmaison, France, by Rene Bernard.

ne Bournonville, executor, Paris, France Application December 17, 1934, sei-lei No. '151,976 -In Belgium December 21, 1933 4 Claims.

The present invention relates to machines'provided with means for the evacuation of calories from some of their elements. Itis more especially, although not exclusively concerned with in- 5 t'ernalcombustion engines, and more particularly those of the fuel injection type.

The object of the present invention is to provide machines of this type which are better adapted to meet the requirements of actual practice. I

According to the present invention, the elements of these machines-that are intended to serve to the evacuation of heat consist of the combination of at least two parts juxtaposed together and one of which is to give off heat to the other one. The essential feature of the present invention consists in so devising these parts that at least portions of their faces constitute walls of a closed chamber'which is filled with a compressed metallic powder.

Preferably, this metallic powder must be a powder of a metal which is a good conductor of heat, for instance aluminium.

These, and other, features of thepresent invention willfclearly result from the following detailed description of some specific embodiments of saidinvention.l

Preferred embodiments of the present invention will be hereinafter described, withfreference to the accompanying drawing, given merely by way of example, and in which: f

Fig. 1 is an axial vertical sectional view of the upper part of a cylinder and vthe corresponding piston of a fuel injection internal combustion engine made according to the invention;

Fig. 2 is an axial vertical sectional view of the A cylinder head of an explosion engine of the valve type showing another manner of employing the present invention.

40 The embodiments of the present invention that will be hereinafter described illustrate the application of the invention to an internal combustion engine.

In an internal combustion engine according to the present invention, all the parts, with the exception of those that must serve to the evacuation of calories, may be made of any suitable conventional or 4other structure. The parts serving to the evacuation of heat consist of the assembly oi at least two elements juxtaposed to each other and one of which must give oil' calories to the other one. For instance. at least some portions of the combustion chamberv of the engine constitute one of these two elements.

' 55 According to the present invention, the heat pressed metallic powder.

(Cl. 12S- 176) chamber, which chamber is filled with com- Advantageously, certain portions of the walls of said chamber are so devised as to ensure the removal of the calories transmitted through said metallic powder. 5

Of course, according to the invention, any metallic powder may be used, but, advantageously,

use should be made oi.' a powder of ametal which is' a good conductor of heat, such for instance as aluminium. l l0 Furthermore, this metal is particularly advantageous in the case of the invention being applied to the pistons of internal combustion engines, be cause it is advantageous to obtain pistons that are as light as possible. l5

An internal combustion engine piston according to thel invention is shown by way of example in Fig. 1. In this embodiment of the invention, the cushion of metallic powder above mentioned is shown at a. A sumcient amount or 'said 2oV metallic powder is poured into the inside of the piston, previously placed upside down, in order to obtain a cushion a of metallic powder compressed and maintained by a partition b of suitable shape. Advantageously, this partition b is positioned 25 below the zone of thepiston skirt carrying the upper packing rings. `Partition b may be provided, on its outer face, that is to say on its face that is not in contact with the cushion a of metallic powder, with cooling ribs or projec- 30 tions c.

When the internal combustion engine piston is of the type including,`in its central portion. a projection d on which is directed and impinges the jet fromthe injector, said projection is advan- 35 tageously carried by a part e, for instance of special steel, which is screwed, or xed in position in any other way, on the body -J of the piston, which is, for instance, made of cast iron. Advantageously, this part e is so hallowed out that 40 the metallic powder may have therewith a surface of contact as large as possible. Furthermore the walls of said part ve can be given a reduced thickness, which is very advantageous because the thermic conductibility of the ma- 45 terial (for instance vspecial steel) of which part e is made is lower than that'of the compressed metallic powder that constitutes cushion a.

Fig. l1 also showsv the application of the invention to the cylinder head of -an internal combustion engine of the type including a tore-shaped combustion chamber g. l

According to this embodiment, the outer walls of said combustion chamber are surrounded by a chamber closed, on the outside by a wall h which is for instance in contact with the cooling water of the engine, or with any suitable cooling fluid.

' The chamber thus surrounding the combustion 6o chamber of the engineis filled with compressed metallic powder.

Fig. 2 shows the application of the invention to internal `combustion engines provided with two valves disposed side by side.

According to this embodiment, instead of providing, in the space locatedl between the pipes leading to the seats of these valves, a thin sheet of water, according to the usual practice (which has the drawback of producing a rapid scaling of this space), a cushion tof metallic powder is pro-l vided in said space. The chamber in which this cushion Iis enclosed is formed by a portion of the cylinder head and a wall or partition i advantageously provided with cooling ribs or projections. These ribs or projections contact with the engine cooling water, which is contained in jacket k.

It will be readilyI understood that, whatever be the specific embodiment, the cushion of metallic powder is perfectly in contact with the surefficient embodiments of the present invention,

faces of the parts between which a flow of calories is to take place, so that thispassage of the calories from one part tothe other will take place under much better.`conditions than if a solid metallic mass had been applied against said surfaces.

As a matter of fact, for practical purposes, it is impossible to obtain that two metallic surfaces are in contact with each other over their whole area.

Two metallic surfaces can contact each other only at certain points, the number of which may be very great but does not ensure a passage of the calories from` one surface to the other as good as if a perfect contact could be obtained.

'Now this perfect contact is obtained in a wholly satisfactory manner through the metallic powder, and even if it so happens that the thermic conductibility of said powder is lower than that of the metal of which it is made, yet the passage of the calories takes place under .much better conditions than if a solid` metallic mass were used.

Another advantage of the use of compressed metallic powder as filling material overthe use of a block of solid material is obtained when said filling material must consist of a metal that is very much dilatable, vsuch as aluminium. This is due to the fact that a powder, due to its elasticity, cannot have any injurious action in spite of its high coefficient of expansion, even when it is enclosed in a chamber made of a material having a coefficient of expansion lower than that of the matter of which the filling cushion is made.

This advantage is particularly great when the parts of the engine, such for instance as a piston or a cylinder head consists of the juxtaposition of elements made of different metals, and therefore having different coefficients of expansion. In this case also, the thermic connection between -these elements is obtained in a much more satisfactory manner with metallic powder than with a block of light metal such as those utilized up to the present time for this purpose.

Furthermore, a compressed metallic powder prevents 'the unscrewing of the various nuts, (such for instance as those serving to fix in position projection d, above mentioned with reference to Fig. 1)` through which the elements are assembled together and it forms a packing element between them.

It should be noted that,l in the case of pistons the last mentioned advantage is Very precious for preventing not only leakage of gases from the combustion chamber, but also, and chiefly, leakage of air and oil from the inside of the piston. As a matter of fact, the last mentioned leakage wouldpermit oil to penetrate into the piston, where it would be calcined, which would subsequeiatly produce dilatations causing seizing or breaking. New;

Finally, in the case' of pistons provided with a projection d of the kind-of that shown in Fig. 1, the presence, under the piston head, of a cushion of compressed metallic powder reinforces the piston head and makes it possible to make -it of a relatively small thickness, in spite of the high temperature to which itis subjected during working and of the relatively bad mechanical properties of themetals of which piston heads are generally made. f

While there are in the preceding description, disclosed what are deemed to be practical and it should be well understood that it is not desired to be limited thereto'as there might be changes made inthe arrangement, disposition ,and form of theparts without departing from the'principle of the present invention as comprehended within the scope of the appended claims.

What is claimed is: 1. In a machine, the combination of at least v two parts made of materials having different respective coefficients of expansion, one of which partsis intended to: give off heat to the other one, when in operation, at least portions of the faces of said parts constituting walls of a closed chamber, and a `metallic powderfilling up said f chamber compressed therein.

' heat off from said parts and to tighten the joints between them.

3. A piston comprising in combination at least two parts made of materials having different respective coefficients of expansion and contacting one another, portions of the faces of said parts adjacent the jointsA betweenthem constituting at least a portion of the walls of a closed chamber, and a metallic' powder filling up said chamber and compressed therein Ato conduct heat off from said parts and to tighten the joints between them.

4. A piston for internal combustion engines, which comprises in combination a piston end, a hollow projection fixed to the central part of said piston end and extending on the outer side thereof, said piston end and said projection being made of materials having different respective coefficients of expansion, a piston skirt, a partition carried by said piston skirt, so as to form inside said piston a closed chamber limited by said piston end, the inside lof? said hollow projection, said piston skirt and said partition, and a metallic powder filling up said chamber and compressed therein.

RENE BERNARD, NE BOURNONVILLE,

Eecutor of Auguste Louis Ren Bernard, Degceased. 1 

